CN108602232B

CN108602232B - Gripper assembly for handling preforms, transfer wheel and container handling machine having such a gripper assembly

Info

Publication number: CN108602232B
Application number: CN201680080994.XA
Authority: CN
Inventors: D·克拉特; R·鲍姆加特; J·F·迈尔
Original assignee: KHS Corpoplast GmbH
Current assignee: KHS GmbH
Priority date: 2016-02-16
Filing date: 2016-11-18
Publication date: 2021-07-09
Anticipated expiration: 2036-11-18
Also published as: DE102016001755A1; EP3416803A1; CN108602232A; WO2017140330A1; EP3416803B1

Abstract

The invention relates to a jaw assembly (50) for handling preforms (1) made of thermoplastic material or containers (2) produced from said preforms, comprising a jaw base (52) and at least two jaw arms (53) pivotably fastened to the jaw base and a jaw carrier (51) carrying the jaw base (52), characterized in that the jaw base (52) is connected to the jaw carrier (51) by means of a four-joint (70), wherein the jaw base (52) and the jaw carrier (51) are designed as respectively opposite arms of the four-joint (70), wherein the four-joint (70) is designed in a complete manner, in particular by means of two pivoting arms (56a, 56b) of the same length. The invention also relates to a transfer wheel having the gripper assembly (50) and to a container treatment machine (45) having a transfer wheel with the gripper assembly (50).

Description

Gripper assembly for handling preforms, transfer wheel and container handling machine having such a gripper assembly

Technical Field

The invention relates to a gripper assembly for handling preforms made of thermoplastic material or containers produced from said preforms, comprising a gripper base, at least two gripper arms pivotably fastened to the gripper base, and a gripper carrier carrying the gripper base.

The invention further relates to a transfer wheel for handling preforms made of thermoplastic material or containers produced from said preforms, comprising at least one carrier arm and at least one gripper assembly fastened to the carrier arm or arms. Finally, the invention relates to a container treatment machine having said jaw assembly. Such as a blow molding machine, a coating machine, a labeling machine, a filling machine or other machines used in connection with the processing or machining of preforms or containers produced from preforms. The container treatment machine can also be composed of a plurality of the aforementioned machines, for example in an interlocking design.

Background

In the formation of containers by the action of blowing pressure, preforms made of thermoplastic material, for example made of PET (polyethylene terephthalate), are transported inside a blow molding machine to various processing stations. Such blow molding machines typically have a heating device and a blow molding device, with the preforms, which are first tempered by means of the heating device, being expanded into containers by biaxial stretching. The expansion is carried out, for example, by means of compressed air introduced into the preform to be expanded. DE 4340291 describes a technical process for such expansion of preforms. The introduction of the gas under pressure mentioned at the outset also includes the introduction of compressed gas into the expanding container bulb and the introduction of compressed gas into the preform at the beginning of the blow molding process.

DE 4212583 describes a basic structure of a blow molding station for forming containers. DE 2352926 describes a possibility for tempering preforms.

Within the device for blow molding, the preform parts and the blown containers can be transported by means of different handling devices. It is known to use, in particular, a conveyor bar onto which preforms are inserted. The preform can however also be handled by means of additional carrying means. The use of the gripper for handling preforms is likewise of an available design, as well as the use of a clamping bar which can be moved into the mouth region of the preform for fastening purposes. The grippers and other gripper assemblies, which are usually composed of a gripper base and gripper arms which are usually pivotably fastened to the gripper base, and a gripper carrier which carries the gripper base, grip the preform or the container from the outside. The neck ring of the preform or container is typically used for gripping purposes. The jaw assembly has the advantage that the mouth region of the preform or container remains freely accessible, for example for the insertion of the handling means into the preform or for the mounting of the handling means onto the mouth region.

The handling of containers using transfer wheels is described, for example, in DE 19906438, wherein a transfer wheel is arranged between the blow-moulding wheel and the output region. Transfer wheels, also called transfer wheels, usually have a plurality of carrier arms which carry the handling devices. The transfer wheel is arranged, for example, on the input side of the blow molding machine and also on the output side of the blow molding machine. The transfer wheel is also arranged, for example, between different container treatment machines in order to enable transfer from a first container treatment machine to a second container treatment machine. However, the transfer wheel can also be arranged inside the container treatment machine, for example, in order to transfer preforms or containers produced therefrom from one treatment station to the next, for example from a heating device to a blow-moulding device. It is also conceivable that the transfer wheel is equipped with a function other than transport. Thus, for example, an extraction device can be arranged on the transport wheel in order to extract preforms determined by the inspection device to be defective or containers produced therefrom. Measuring means are also arranged on the transfer wheel for controlling the processing machine on the basis of measurements made by the measuring means. For example, a wall thickness measuring device or a temperature measuring device or any other measuring device can be provided which detects the properties of the preform or of the container produced therefrom and transmits the detected values to the control unit for machine control purposes and/or for blow molding process control purposes.

On the one hand, the handling of the preforms described above takes place in a so-called two-stage method, in which the preforms are first produced in an injection molding process, then stored intermediately and only then tempered with respect to their temperature and blow molded into containers. On the other hand, use is made in so-called single-stage processes in which the preform pieces are suitably tempered and then blow-molded directly after their manufacture by injection molding techniques and fully cured.

Different embodiments are known with regard to the blow molding station used. In the blowing station, which is arranged on a rotating transport wheel, i.e. on a so-called blowing wheel, a book-like turnability of the mold carrier is achieved. However, it is also possible to use mold carriers that are movable relative to one another or are otherwise guided. In stationary blow molding stations, which are particularly suitable for receiving a plurality of cavities for blow molding, plates arranged parallel to one another are typically used as mold carriers.

Prior to heating, the preforms are typically inserted onto a transport rod which either transports the preforms through the entire blow molding machine or only moves in a circulating manner in the region of the heating device. In the case of vertical heating, in which the mouth of the preform is oriented downward in the vertical direction, the preform is usually inserted onto a sleeve-like fastening element of the conveying rod. In the case of suspension heating of the preform with its mouth oriented upward in the vertical direction, spreader struts usually enter the mouth of the preform, which grip the preform.

In the region of the heating zone, there is a typical requirement to achieve a uniform temperature control in the circumferential direction of the preform. In contrast, in certain applications, so-called Preferential Heating (Preferential Heating), there is a requirement to specify an inhomogeneous temperature distribution that is precisely defined in the circumferential direction of the preform. This method is used, for example, when a container is to be produced, the cross section of which differs from a circular shape. Said difference may for example enable the production of containers with an elliptical cross section or, for example, with a triangular or quadrangular cross section.

The manufacture of such non-round containers has been described in US 3,775,524. There, the preform is first uniformly tempered and the temperature is then selectively increased in selected regions. Further variants for generating a temperature profile in the circumferential direction of the preform are described in US 3,632,713, US 3,950,459 and US 3,892,830. Tempering by selective masking is given in DE 3314106.

It is known from US 5,292,243 to subject two preforms simultaneously to a tempering treatment in the circumferential direction. EP 0620099 discloses a combination of methods known from the prior art for tempering preforms.

In particular, it is also described in said publication that the preforms are guided past an alternating arrangement of heating elements and cooling zones in such a way that a desired temperature profile is provided by coordinating the spacing and the extent of the respective heating devices with the translation speed and the rotation speed of the preforms guided past. However, this arrangement requires a large spatial extension, which necessitates exact adaptation of a plurality of parameters to one another, and adaptation to different product requirements is very complicated.

DE 19608570 describes a method in which a simplified structural realization is achieved by stepwise rotation of a preform provided with a temperature profile. DE 19757818 describes a method and a device in which a preform is held by a carrier element which can be pivoted about its longitudinal axis by cam rollers along cam tracks in a manner which interacts with one another and thus facilitates the application of a temperature profile in the axial direction. The device is particularly suitable for tempering a large number of preforms per heating unit. However, here too, a change in the product requirements leads to relatively high change costs.

In order to support the two mentioned possible requirements for the temperature control of preforms, namely on the one hand to achieve a uniform temperature control in the circumferential direction of the preform and on the other hand to provide for other applications (Preferential Heating) a non-uniform temperature distribution which is precisely defined in the circumferential direction of the preform, it is expedient to provide that the preform is passed through the Heating zone along its transport path in a rotation about its longitudinal axis. The rotation may be uniform to support an even temperature distribution or defined non-uniform to support the generation of a predetermined thermal profile.

The possibility for introducing such a rotational movement into the preforms is that the carrier elements for the preforms are provided with toothed wheels which roll in chains which extend along the transport path of the preforms. The chain can be arranged immovably, so that the circumferential speed of the preforms is directly related to their translational speed. However, it is also known to provide the chain with a drive so that the chain moves cyclically along the guide element.

In the case of such chains, the chain is typically laid out in such a way that the chain run-ahead is arranged along the conveying path of the preforms on the outside and the return of the chain runs further outside. The forward and return paths of the chain thus open out a horseshoe-like basic structure which surrounds the heating zone on three sides, wherein the horseshoe-like structure is open toward the blow-molding module in which the heating zone is arranged. The horseshoe-like basic structure allows the preforms to be transported into and out of the heating modules without limiting the range of movement.

The arrangement of the run-out and run-back regions of the chain substantially parallel to one another, however, leads to a chain length which includes the necessary deflection and which is more than twice as long as the actual effective region for achieving the contact with the gear of the carrier element. This results in a corresponding expenditure of the chain, but in particular in a corresponding chain weight which impairs the dynamic behavior of the overall system.

DE 102007016027 a1 describes a chain guide device in contrast to this. The chain is arranged in such a way that it is guided in a closed loop along the heating zone. The chain length is reduced in the manner described.

The preforms (preferably heated) provided with a temperature profile in the circumferential direction as described above must be transferred into the blow mold at the end of the passing Heating zone. In this transfer, the preforms are transferred in a defined orientation, since the strongly heated circumferential regions of the preforms must be aligned in a defined manner with the blow mold. To achieve the object, different solutions are disclosed in the prior art. Thus, for example, WO 97/32713 describes that the preform may be provided with indicia. It is described that when the container has a detectable marking or a machine readable structure, this may facilitate later handling of the blow molded non-round container. Different examples of markers are given, for example in the case of optical detection of the rotational orientation. Further examples are given for mechanically detecting the rotational orientation. The purpose of the marking is to assume a predefined position during the production of the container and during the tempering of the preform, so that during the entire production process and during subsequent handling, there is an exactly known rotational orientation of the preform, of the possible intermediate products and of the blow-molded container. The rotational orientation here relates to the position which is assumed in accordance with a rotation about the longitudinal axis of the preform or of the container blow-molded therefrom, respectively.

DE 19757818 a1 discloses for a rotational orientation that an orientation pin is formed on the conveyor bar, which pin interacts with the guide rail. The preforms transported by the transport rods are brought into a defined rotational orientation in this manner. Due to the rotationally fixed connection between the conveying rod and the preform held by the conveying rod, the rotational orientation of the preform is also ensured by the rotational orientation of the conveying rod.

The aforementioned measures for the rotational orientation of the preform also have disadvantages. The arrangement of the orientation pin on the lever, for example, is therefore not suitable for handling processes in which the lever is not used. The provision of optically or mechanically or otherwise detectable marks on the preforms requires considerable detection and control effort and a corresponding adaptation to the preform used.

Disclosure of Invention

The object of the invention is to improve a method of the type mentioned at the outset in such a way that high-quality heating is supported with low outlay on machine construction. The object of the invention is, in particular, to support the rotational orientation of the preform or of the container produced therefrom while being transferred by means of the jaw assembly.

This object is achieved according to the invention in that the clamp base is connected to the clamp carrier by means of a four-joint. The forceps base and the forceps carrier are arranged and designed as four-joint, respectively opposing limbs. The four-joint is constructed in particular in full by two opposing pivot arms which each extend from the caliper base to the caliper carrier, wherein the two pivot arms preferably have the same length.

A further object of the invention is to provide a transfer wheel and a container treatment machine which provide an improved solution for the rotational orientation of preforms or containers produced therefrom.

This object is achieved according to the invention in that the transfer wheel has at least one carrying arm with a jaw assembly according to the invention. This object is achieved with respect to a container treatment machine having a transfer wheel according to the invention.

According to the invention, the clamp base is connected to the clamp carrier by means of a four-joint. A four-joint is understood to mean a coupling gear comprising four arms and four pivot axes, wherein the two arms are connected to each other so as to be pivotable on one pivot axis. According to the invention, two of the swivel axes are located on the calliper base and the other two on the calliper carrier. The forceps carrier and the forceps base are connected to each other by two arms. The clip carrier and clip base form two remaining arms to complete the four-joint construction.

This proposed design has the advantage that, by means of the pivoting movement of the two gripper arms connecting the gripper base and the gripper carrier, a precise movement of the gripper arms articulated on the gripper base and thus a precise movement of the workpiece (preform, container) held by the gripper arms can be achieved. This movement of the workpiece may be a translational movement or a rotational movement or a combination of said translational and said rotational movement.

The forceps base and the forceps carrier advantageously form four-joint, respectively opposite limbs. It is furthermore advantageously provided that the four-joint is formed completely by two pivot arms, in particular by two pivot arms of the same length. The same length of the oscillating arm has the advantage of a simple movement pattern when performing the oscillating movement. In particular, it can be achieved in this way that the jaw assembly rotates the workpiece (preform, container) held by the jaw assembly by means of a pivoting movement of the pivot arm, without the workpiece changing position in the respective end position of the pivoting movement of the jaw assembly. That is to say, for example, a workpiece that is rotationally symmetrical about a longitudinal axis, as is the case with a preform and a container produced from the preform, can be pivoted by the oscillating movement of the oscillating arm, and the longitudinal axis of the workpiece can be in the same position here before the oscillating movement is carried out and after the oscillating movement is ended. However, in the intermediate phase of the pivoting movement of the jaw assembly, i.e. after leaving the starting position when the pivoting movement is started and before the end position of the pivoting movement is reached, the longitudinal axis of the workpiece can be moved in space. The above-described investigation of the position fixity relates to the relative position with the gripper carrier, which of course normally itself is moved, since the gripper carrier is arranged, for example, on a transfer wheel. The rotary movement of the transfer wheel is correspondingly superimposed on the above-mentioned oscillating movement and also on the rotary movement of the workpiece. However, the longitudinal axis of the workpiece is in the same position before and after the swiveling movement, as observed by the gripper carrier and the viewer moving on the gripper carrier.

In order to achieve a specific movement pattern, the length of the pivot axis, the length of the gripper arm and the pivot angle can be geometrically simply taken into account and adapted to one another in such a way that the desired movement pattern is implemented. This applies in particular to the advantageous embodiment variant described below, in which the preform is rotated about its longitudinal axis while the position of the longitudinal axis of the workpiece remains unchanged at the start and end positions of the pivoting movement. The described embodiment of the gripper assembly makes the transfer process particularly simple, since the transfer point of the workpiece is not changed by the described pivoting movement. In other words, the jaw arrangement can be used without complex retrofitting work both in the case of preferential heating and in the case of uniform tempering of the preforms. In the latter case, for example, the pivoting movement of the jaw assembly may not be performed. The transfer is thus not influenced in any way, since the transfer point can be kept unchanged by a suitable choice of the length and pivot angle relationships of the four-joint system, as described above.

In the preferred embodiment variant described, the gripper arms held by the gripper base and the preform held by the gripper arms define an axis of rotational symmetry of the preform, which is arranged in the middle between the gripper arms. The length of the pivot arm is defined here as the distance between the two pivot axes of the four-joint. The preform longitudinal axis or the container longitudinal axis is also displaced during the pivoting of the four-bar joint relative to the jaw carrier. However, in the case of a preferred selection of oscillating arms having the same length and in the case of a symmetrical end point for oscillating the four-joint about the axis of symmetry of the jaw carrier, the center point of the preform is in the same distance from the jaw carrier in the two end points. In this way, a pure rotational movement of the preform about its longitudinal axis is achieved, while the preform center point remains fixed in position relative to the gripper carrier in the two end points of the pivoting movement. The movement of the center point of the preform occurs only during the movement phase between reaching the end point. The preform center point and the longitudinal axis of the preform are used synonymously in the sense that the preform center point represents the position of the intersection of the longitudinal axis of the preform with the plane spanned by the rotating gripper carrier.

It is advantageously provided that the jaw arrangement has at least one stop for the unilateral limitation of the pivoting movement of the four-joint, in order to specify a defined desired position of the jaw arm. The setting of the stop can be realized in a technically simple manner and ensures accurate repeatability of the movement.

The jaw assembly advantageously has a return stop for holding the four-bar joint in the stop position, wherein the return stop is in particular designed as a magnet and/or as a toggle lever, for example, in the over-dead-center position. This ensures that unintentional pivoting movements of the jaw assembly are not carried out in a structurally simple manner.

Further improvements in the repeatability and accuracy of the movement of the jaw assembly are achieved by providing the jaw assembly with a two-sided stop or two one-sided stops for specifying two defined nominal positions of the jawarms. The nominal positions are usually the starting and end positions of the pivoting movement of the four-joint.

The jaw base and the jaw carrier are advantageously of different lengths, since a rotary movement of the jaw base and the jaw arm articulated thereto relative to the jaw carrier can thereby be realized in a simple manner. Otherwise, a relatively complex kinematic structure is provided for this purpose in order to pivot the forceps arms relative to the forceps carrier during the four-joint pivoting.

The jaw base is advantageously designed shorter than the jaw carrier. This means that the distance of the pivot axes on the forceps base is smaller than the distance of the pivot axes on the forceps carrier, for example, by measuring the position of the respective geometric pivot axis, i.e. the geometric axis about which the pivot axis can pivot. The geometric axis position usually coincides with the actual position of the oscillation axis. The advantage of the dimensioning is that the direction of oscillation of the four-bar joint and the direction of rotation of the pliers base are thus reversed. In this way, a return movement of the preform center point itself can be achieved, which means that the longitudinal axis of the preform or container is located at the same point in relation to the gripper carrier at the starting and end points of the pivoting movement.

A structurally simple embodiment of the pliers arrangement is achieved in that the pivot axis of the pliers leg is formed by a four-joint pivot axis on the pliers base.

Different alternatives regarding the control of the jaw assembly are known in the prior art. Preferably, the jaw assembly is cam-controlled configured, thereby achieving a high degree of accuracy, repeatability and reliability. For this purpose, the jaw assembly has a control element, in particular a follower, for example a cam roller, for interacting with an external cam control device, in particular with an external control cam, wherein the pivoting movement of the four-joint can be cam-controlled at least in one direction. A cam control with a two-sided action can also be considered in order to further increase the movement accuracy.

If no cam control is provided, which acts on both sides, a pivoting movement of the four-joint in the other direction, i.e. from the end position to the starting position, is advantageously carried out by means of a return device, which is in particular designed as a spring. In an alternative embodiment, the jaw assembly can also be designed for cam-controlled pivoting movement of the four-joint in the other direction.

The invention can be used advantageously on a transfer wheel for handling preforms made of thermoplastic material or containers produced from said preforms, which transfer wheel has at least one carrier arm and at least one gripper assembly according to the invention fixed to the carrier arm. The invention is also preferably implemented in a container treatment machine, in particular a blow molding machine and/or a coating machine and/or a labeling machine and/or a filling machine, which has a transfer wheel according to the invention. The advantages result from the advantages of the jaw assembly.

Drawings

Embodiments of the invention are schematically illustrated in the drawings. In the drawings:

figure 1 shows a perspective view of a blow-moulding station for making containers from preforms,

fig. 2 shows a longitudinal section through a sectioning blow mold, in which a preform is stretched and expanded,

figure 3 shows a diagram for explaining the basic structure of an apparatus for blow-moulding containers,

figure 4 shows a modified heating zone with increased heating capacity,

FIGS. 5a, 5b, 5c, 5d show different views of a first embodiment of a jaw assembly according to the present invention, an

Figures 6a, 6b, 6c, 6d show different views of a second embodiment of the jaw assembly according to the present invention.

Detailed Description

Fig. 1 to 4 illustrate typical applications in the field of blow molding machines according to one exemplary embodiment for a blow molding machine without limiting the generality of the jaw assembly and the application possibilities of the jaw assembly to other processing machines for preforms and/or containers.

Fig. 1 and 2 show the principle of a device for forming preforms (1) into containers (2).

The device for forming the containers (2) is essentially formed by a blow-moulding station (3) which is provided with a blow-moulding tool (4) into which the preforms can be inserted. The preform (1) can be an injection-molded part made of polyethylene terephthalate. In order to insert the preform (1) into the blow mould (4) and to remove the finished container (2), the blow mould (4) is formed from mould halves (5, 6) and a base part (7) which can be positioned by a lifting device (8). The preforms (1) can be held in the region of the blow-moulding station (3) by a transport rod (9) which passes together with the preforms (1) through a plurality of processing stations in the device. However, it is also possible to insert the preform (1) directly into the blow mold (4) by means of pliers or other handling devices. This can be done in particular without the use of a feed rod, but with the jaw assembly according to the invention.

In order to achieve compressed air supply, a joint piston (10) is arranged below the conveying rod (9), said piston supplying compressed air to the preform (1) and simultaneously sealing it against the conveying rod (9). In principle, however, it is also conceivable to use a fixed compressed air supply in alternative designs.

The stretching of the preform (1) takes place in this exemplary embodiment by means of a stretching rod (11) which is positioned by a cylinder (12). According to a further embodiment, the mechanical positioning of the stretching rod (11) is performed by a cam section which is loaded by the application roller. The use of cam segments is particularly advantageous when a plurality of blow-moulding stations (3) are arranged on a rotating blow-moulding wheel.

In the embodiment shown in fig. 1, the stretching system is configured such that a tandem arrangement of two cylinders (12) is provided. The stretching rod (11) is first moved by the primary cylinder (13) up to the area of the bottom (14) of the preform (1) before the actual stretching process begins. During the actual stretching process, the primary cylinder (13) together with the extended stretching rod together with the carriage (15) carrying the primary cylinder (13) is positioned by the secondary cylinder (16) or by a cam control. In particular, it is conceivable that the secondary cylinder (16) is used cam-controlled in such a way that the current stretching position is predefined by guide rollers (17) which slide along the cam track during the stretching process. The guide rollers (17) are pressed against the guide rail by a secondary cylinder (16). The carriage (15) slides along two guide elements (18).

After closing the mold halves (5, 6) arranged in the region of the carriers (19, 20), the carriers (19, 20) are locked relative to one another by means of a locking device (40).

In order to adapt to the different shapes of the mouth section (21) of the preform (1), a separate threaded insert (22) is used in the region of the blow mold (4), as shown in fig. 2.

Fig. 2 shows the preform (1) in dashed lines in addition to the blown container (2) and schematically shows the expanding container bulb (23).

Fig. 3 shows the basic structure of a blow molding machine provided with a heating zone (24) and a rotating blow wheel (25). Starting from a preform feed (26), the preforms (1) are transported by transfer wheels (27, 28, 29) into the region of the heating zone (24). Along the heating zone (24), a heat radiator (30) and a blower (31) are arranged in order to adjust the temperature of the preform (1). After sufficient tempering of the preforms (1), the preforms are transferred to a blow wheel (25), in the region of which a blow station (3) is arranged. The containers (2) subjected to blow moulding are conveyed by a transfer wheel to an output zone (32).

In order to be able to mold the preform (1) into a container (2) in such a way that the container (2) has material properties which ensure long-term availability of the food, in particular beverage, filled in the container (2), specific method steps must be followed in the heating and orientation of the preform (1). Furthermore, advantageous effects can be achieved by complying with specific dimensional specifications.

Different plastics can be used as thermoplastic material. For example, PET, PEN or PP can be used.

The expansion of the preform (1) during the orientation process is carried out by compressed air delivery. The compressed air supply is divided into a pre-blowing phase, in which a gas with a low pressure level, for example compressed air, is supplied, and a subsequent main blowing phase, in which a gas with a higher pressure level is supplied. Compressed air having a pressure in the interval of 10bar to 25bar is typically used during the pre-blowing phase and compressed air having a pressure in the interval of 25bar to 40bar is delivered during the main blowing phase.

It can also be seen from fig. 3 that in the embodiment shown, the heating zone (24) is formed by a plurality of cyclically moving conveying elements (33) which are arranged in succession in a chain-like manner and are guided along a deflecting roller (34). It is particularly contemplated that the substantially rectangular basic contour is unfolded by a chain arrangement. In the embodiment shown, one single relatively large-sized deflecting roller (34) is used in the region of the heating zone (24) facing the extension of the transfer roller (29) and the input roller (35), and two relatively small-sized deflecting rollers (36) are used in the region of the adjacent deflecting sections. In principle, any other guide device is also conceivable.

In order to achieve a very compact arrangement of the transfer wheel (29) and the input wheel (35) relative to each other, the arrangement shown is particularly expedient, since the three deflecting wheels (34, 36) are positioned in the region of the respective extension of the heating zone (24), to be precise the smaller deflecting wheel (36) is positioned in the transition region to the linear extension of the heating zone (24) and the larger deflecting wheel (34) is positioned in the transfer region directly to the transfer wheel (29) and the input wheel (35). Instead of using a chain-like conveying element (33), it is also possible, for example, to use a rotating heating wheel.

After the blow-moulding of the containers (2) has been completed, they are removed from the region of the blow-moulding station (3) by an extraction wheel (37) and transported to an output zone (32) by a transfer wheel (28) and an output wheel (38).

In the modified heating zone (24) shown in fig. 4, a large number of preforms (1) can be tempered per time unit by means of a large number of heat radiators (30). The fan (31) introduces the cooling air into the region of cooling air ducts (39) which are each opposite a respective heat radiator (30) and which discharge the cooling air via outlet openings. The arrangement of the outflow direction provides that the flow direction of the cooling air is substantially transverse to the conveying direction of the preforms (1). The cooling air duct (39) can provide a reflector for the heat radiation in the region of the surface opposite the heat radiator (30), it also being possible to achieve a cooling of the heat radiator (30) by the outgoing cooling air. The specific configuration of the heating zones and the heat radiators used and/or the cooling blowers is however not critical to the invention and is selected from the structures known from the prior art. For example, cooling blowers may be absent as desired.

The transfer wheels (27), (28), (29) and the input wheel (35), the pick-up wheel (37) and the output wheel (38) shown in fig. 3 have a carrying device in order to be able to handle the preforms or the containers produced from them. An embodiment of the load bearing device according to the invention, i.e. of the jaw assembly (50) according to the invention, shall be described below. The gripper assembly (50) can be arranged at any point on the blow molding machine described in relation to fig. 3, but also at suitable points in other container treatment machines and at the transfer region between container treatment machines arranged one behind the other. Thus, the jaw assemblies (50) described below may also be provided, for example, on transfer wheels arranged on the output side of the blow molding machine and on the input side of the filling machine. In a similar manner, it is possible to arrange the transfer wheel between any other machines for processing preforms or for processing containers produced from preforms.

Fig. 5a shows the jaw assembly (50) with the jaw carrier (51) in a top view. The gripper carrier (51) can be fastened, for example, to a carrier arm, wherein the carrier arm can be arranged, for example, on one of the transfer wheels. The jaw assembly (50) also has a jaw base (52). Two gripper arms (53) are arranged symmetrically on the gripper base (52) with respect to a common axis of symmetry. The gripper arms (53) have gripping areas (54) at one end thereof, for example, for gripping a neck ring of a preform (1) or a container (2). At the end facing away from the gripping area (54), the gripper arms (53) are pivotably articulated on the gripper base (52). For this purpose, two pivot axes (55a) and (55b) are provided, which have a common center distance. The geometrical pivot axis of the gripper arm (53) coincides with the axial center of the mechanical pivot axes (55a, 55b), so that the center-to-center distance of the pivot axes (55a, 55b) is equal to the distance between the two geometrical pivot axes of the gripper arm (53). The gripping area (54) of the gripper arms (53) is oriented towards a partial circle which encloses the center of symmetry (X) of the enclosing area. Preferably, the longitudinal axis of the preform (1) or of the container (2) held by the jawarms (53) coincides with said centre of symmetry (X), for example.

The forceps base (52) is connected to the forceps carrier (51) in an articulated manner by means of a first swivel lever (56a) and by means of a second swivel lever (56 b). The two mentioned pivot levers (56a, 56b) are pivotably mounted on the gripper carrier (51) on the gripper carrier side by means of a pivot axis (57a) or (57 b). The pivoting levers (56a) and (56b) are articulated on the gripper base side on a pivoting axis (55a) or (55b) on the gripper base (52), wherein in the exemplary embodiment shown the pivoting axis (55a) and the pivoting axis (55b) simultaneously serve as pivoting axes for in each case one gripper arm (53) and for one pivoting lever (56a, 56 b). However, it is also conceivable to provide a separate pivot axis for the pivoting movement.

As is evident from the lower view shown in fig. 5b, the two gripper arms (53) are preloaded into position at their ends opposite the gripping region (54) by a spring (58) located between the two gripper arms. Against the spring force of the spring (58), the preform (1) can be pressed, for example, into the space enclosed by the gripping region (54) of the gripper arm (53) and is then held clamped by the gripper arm (53) with a corresponding dimensioning of the preform (1).

Fig. 5b and 5c show the jaw assembly (50) in two different positions, respectively, in a view from below. Fig. 5b shows the starting position of the jaw assembly (50) and fig. 5c shows the end position of the jaw assembly (50). It is to be noted that in the exemplary embodiment shown, the axis of symmetry (X) is arranged unchanged in its position relative to the jaw carrier (51), both in the starting position and in the end position.

The gripper base (52), the pivoting levers (56a) and (56b) and the gripper carrier (51) form a four-joint (70) having four pivoting axes (55a), (55b), (57a) and (57 b). The pivoting movement by the gripper arms (53) is defined by the center distance between the pivot axes (57a, 57b), by the pivot axis length of the pivot lever (56b), i.e., by the center distance between the pivot axes (57b, 55b), by the center distance between the pivot axes (57a, 55a) and by the center distance between the pivot axes (55a, 55 b). Finally, the length of the gripper arms is also the distance between the axis of symmetry (X) and the pivot axis center of the pivot axis (55a) or (55 b).

The four-bar linkage (70) is actuated by an external cam control, wherein fig. 5a to 5c show the cam rollers with the reference number (59). The cam roller works with an external control cam (65), which is only shown in fig. 5 c.

The swing lever (56a) is connected to the cam roller (59) via a toggle link mechanism (66). Fig. 5c shows the toggle lever mechanism (66) in the over-dead-center position. The four-joint (70) is fixed in position in the over-dead-center position, in particular because the spring (60) holds the toggle lever mechanism (66) in the over-dead-center position. External forces acting on the cam roller (59) are required in order to move the four-bar joint (70) out of the position shown in fig. 5 c.

In the position of the four-joint (70) assumed in fig. 5b, the same spring (60) also functions in a positionally stable manner, since it must be extended in order to move the cam roller (59) from the position shown in fig. 5b to the position shown in fig. 5 c. Both the starting position shown in fig. 5b and the end position shown in fig. 5c are thus realized with a return stop. The return stop is realized by a spring (60). Other configurations of the return stop means are also contemplated.

The spring (60), which brings the elements of the jaw assembly (50) into abutment against the stop, effects the positioning of the four-joint (70) as shown in fig. 5b and 5 c. The stop in the exemplary embodiment shown in fig. 5b forms a stop magnet (61). The stop magnet (61) has the additional task of fixedly holding a pivot lever (62), which is made of a magnetizable material at least in its stop region (63), in a position abutting against the stop magnet (61). Alternatively, a stop body can also be provided, into which a magnet for fixing the stop position is inserted. In this case, the magnet acts in a positionally stable manner in addition to the toggle lever arrangement (66) and the spring (60). The design of a non-magnetic position stabilization device is likewise conceivable, as is the case with a magnetic position stabilization device alone, if necessary supplemented by a spring (60) and/or by a toggle lever mechanism (66).

Figure 5d illustrates the two previously described swing positions of the jawset for figures 5b and 5c in an isometric view and to make the geometry and arrangement of the foregoing elements of the jawset of the embodiment clearer.

Fig. 6a to 6c show a second embodiment for a jaw assembly (50) according to the invention in a view similar to fig. 5a to 5 c. Only the modifications of the second embodiment, which are different from the first embodiment already described, should be described below. The same reference numerals are used for the same components.

In order to stabilize the starting and end positions of the pivoting movement of the four-joint linkage (70), the jaw assembly (50) of fig. 6a to 6c has neither a spring nor a toggle lever mechanism with an over-dead-center position. More precisely, in this embodiment, the starting position and the end position are predefined by an external cam control and by the cam roller (59) resting against an external control cam. Furthermore, there is a structural consistency in that the forceps carrier (51) and the forceps base (52) form two limbs of a four-joint (70). The two remaining arms of the four-joint (70) in the form of swivel levers (56a, 56b) extend between the forceps carrier (51) and the forceps base (52). The swivel levers (56a) and (56b) are connected in an articulated manner to the forceps carrier (51) or to the forceps base (52) on the forceps carrier side and on the forceps base side on swivel axes (55a), (55b), (57a) and (57b) in a manner known from the first exemplary embodiment.

Figure 6d shows the two previously described swing positions of the jawset for figures 6b and 6c in an isometric view and makes the geometric relationships and arrangement of the foregoing elements of the second embodiment of the jawset more clear.

List of reference numerals

1 preform

2 Container

3 blow moulding station

4 blow molding die

5, 6 mould halves

7 bottom part

8 lifting device

9 holding element

10 joint piston

11 stretch rod

12 cylinder

13 primary cylinder

14 bottom of preform

15 sliding seat

16 sub-cylinder

17 guide roller

18 guide element

19, 20 blow mould carrier

21 mouth segment

22 threaded insert

23 container bulb shell

24 heating zone

25 blow molding wheel

26 preform input

27-29 transfer wheel

30 heat radiator

31 blower

32 output area

33 conveying element

34 steering wheel

35 input wheel

36 steering wheel

37 take out wheel

38 output wheel

39 cooling air channel

40 locking device

42 bearing arm

45 container processing machine, blow molding machine

50 pincers assembly

51 pincers bearing member

52 pincers base

53 tong arm

54 grab area

55a, 55b oscillating shaft

56a, 56b oscillating lever

57a, 57b oscillating shaft

58 spring

59 driven member

60 spring

61 magnet

62 oscillating lever

63 stop area

65 external control cam

66 toggle

70 four-joint.

Claims

1. A jaw assembly (50) for handling preforms (1) of thermoplastic material or containers (2) produced therefrom, the forceps assembly comprises a forceps base (52), at least two forceps arms (53) which are fixed on the forceps base in a swinging mode, and a forceps bearing piece (51) which bears the forceps base (52), characterized in that the clamp base (52) is connected to the clamp carrier (51) by means of a four-joint (70), wherein the forceps base (52) and the forceps carrier (51) are designed as respectively opposing limbs of the four-joint (70), wherein the four-joint (70) is constructed completely by two oscillating arms (56a, 56b) of the same length, and the pivot axes (55a, 55b) of the gripper arms (53) are formed by pivot axes of the four-joint (70) on the gripper base (52).

2. The jaw assembly (50) according to claim 1, wherein said jaw assembly (50) has at least one stop (61, 63) for limiting the pivoting movement of said four-bar linkage (70) on one side in order to predetermine a defined nominal position of said jawarms (53).

3. The jaw assembly (50) according to claim 2, wherein the jaw assembly (50) has a return stop means (61, 63, 66, 60) for holding the four-bar linkage (70) in a stop position, wherein the return stop means is configured as a magnet (61) and/or as a toggle lever (66) in an over-dead-center position.

4. The jaw assembly (50) according to claim 2 or 3, wherein said jaw assembly (50) has a two-sided stop or two one-sided stops for predetermining two defined nominal positions of said jawarms (53).

5. The jaw assembly (50) of any of claims 1-3, wherein the arms formed by said jaw base (52) and the arms formed by said jaw carrier (51) are configured at different lengths.

6. The jaw assembly (50) of claim 5, wherein an arm formed by said jaw base (52) is configured to be shorter than an arm formed by said jaw carrier (51).

7. The jaw assembly (50) according to one of claims 1 to 3, characterized in that the jaw assembly (50) is cam-controlled and has a control element for interaction with an external cam control, wherein the pivoting movement of the four-bar joint (70) can be cam-controlled at least in one direction.

8. The jaw assembly (50) according to claim 7, wherein said jaw assembly (50) has a return means for an oscillating movement of said four-joint (70) in the other direction, said return means being configured as a spring (60).

9. The jaw assembly (50) of claim 7, wherein said jaw assembly (50) is configured for cam-controlled oscillating movement of said four-bar linkage (70) in a further direction.

10. The jaw assembly (50) of claim 7, wherein said control member is a follower (59) and said external cam control means is an external control cam (65).

11. Transfer wheel (27, 28, 29, 35, 37, 38) for handling preforms (1) or containers (2) manufactured from thermoplastic material, having at least one carrier arm (42) and at least one jaw assembly (50) according to one of the preceding claims fixed on the carrier arm (42).

12. A container handling machine having a transfer wheel (27, 28, 29, 35, 37, 38) according to claim 11.

13. The container treatment machine according to claim 12, characterized in that it comprises a blow moulding machine (45) and/or a coating machine and/or a labelling machine and/or a filling machine.